Fig. 1
Experimental design of K. quasipneumoniae colonization and pH of GI. A The design of the study of mice gut colonization by K. quasipneumoniae. 1st Vehicle-only control group with natural microbiota (n = 3); 2nd Bacterial control group (n = 3); 3rd, 4th antibiotic pre-treated groups [(i) penicillin, streptomycin (pen_strep group) or (ii) penicillin, streptomycin, and metronidazole (pen_strep_met group)]. Samples were collected on circled days. B The pH values measured in the samples of rectum excreta throughout the layout of the experiment protocol in order to determine the changes in the GI tract using different substances. The control group showed an average of 7.34 pH with the lowest being 6.99 pH and the highest 7.76 pH; the infected mice group without antibiotics showed almost no changes in pH measures through the days (av. 7.27 pH); K. quasipneumoniae infected group was treated with antibiotic therapy (penicillin, streptomycin) and showed stable results (av. 7.7 pH) with an exception on the 6th day of the experiment (7.94 pH); the last group, which was infected with K. quasipneumoniae showed the most noticeable changes during the combined antibiotic (penicillin, streptomycin, metronidazole) treatment and bacterial colonization with the average of 7.44 pH fluctuating from 6.57 pH to 8.11 pH. No significant differences were found in or between the groups. C Overall differences in values of stomach, duodenum, and rectum of pH measurements between groups. The lowest pH was seen in the stomach (2.34 – 5.46; avg. 3.3). The pH of the small intestine varied between 5.97 and 6.77 (avg. 6.5), with the large intestine showing the highest pH (6.74–8.15; avg. 7.4). A significant difference (p < 0.05) in pH measures was found in the duodenum between 3rd and 4th groups (#), as well as between 1st group and 3rd (*) in rectum